Whether to balance wings of different weights:

I have completed wing panels that differ significantly in weight. A
63" wing span when assembled. The wings are both balanced around the
4th rib, but one wing seems to weigh 2-3 oz more than the other. I am
going to buy a grocery scale to measure with some degree of accuracy
what that difference is and consider adding weight to the other wing.
The heavy wing was built with twice the CA that the other wing was,
could glopping CA make that big a difference in weight once dry?
Reply to
Sisyphus
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I'd use a fish scale. Accurate to 1/2 ounce.
Yes. CA "cures", it doesn't "dry". If you use 2 ounces of CA while building, you'll have 2 ounces when it's done.
If the wings are out 2-3 ounces, I'd balance them, but balance the whole plane, not just the wing. You'll find when the wing is attached to the fuselage the lateral balance will be different. Dr.1 Driver "There's a Hun in the sun!"
Reply to
Dr1Driver
Oh my god, I just fell off my chair! That is the most stupid comment I have read this week.
Dr1, how do you come to such a ridiculous conclusion?
Reply to
Bill
OK smart ass, what's your opinion? Some glues set by evaporation, some by curing. In the case of evaporation, a little weight is lost. In the case of curing, that you start with is what you end up with. Dr.1 Driver "There's a Hun in the sun!"
Reply to
Dr1Driver
Hey Bill, read Glue 101 before you type a whopper like your comment to Dr. 1. Why the heck would you write such a caustic response to him about something about which you obviously know next to nothing?
CA polymerizes and solidifes when catalyzed by the presence of various substances on the materials being glued, and/or when helped by a shot of "kicker" which is an aromatic amine catalyst in a solvent carrier. It does NOT "dry" which is a process whereby solvents evaporate leaving behind solids. Adhesives that "dry" undergo a loss of mass equal to the solvents lost. Adhesives that cure do not, except for perhaps negligible weight loss due to small amounts of volatiles escaping.
If CA "dried" then try explaining how it can do that in 1 second, and why thin CA "dries" the fastest.
Epoxies cure.
Epoxy paints flash off solvents first, then cure.
Polyester resins cure when catalyzed with (typically) MEKP.
White glue dries.
Plastic model cement dries.
Ambroid dries.
Nail polish dries.
Tremclad dries.
Mud dries.
CA cures.
Mike D.
Reply to
M Dennett
DRY CA is considerably lighter than WET CA.
I would suggest you go and discover the meaning of the words WET and DRY!
Reply to
Bill
Prove that with RELIABLE, FACTUAL statistics. Let me see some manufacturer's or research lab tables Dr.1 Driver "There's a Hun in the sun!"
Reply to
Dr1Driver
Oh my god, I just fell off my chair again! That is the second most stupid comment I have read this week.
manufacturer's
Reply to
Bill
Take a fresh bottle of CA, weigh it, squirt some accelerator into it (and jump out of the way), and then weigh it again when it's set. The bottle of glue will weigh the same (if you take into account the amount that boiled over and/or flew somewhere else).
or easier on the pocketbook
get a gram scale and an epoxy mixing cup, squirt in a gram or 2 of CA, hit it with the accelerator and weigh it after it's set. It'll weigh the same
Don
Reply to
Don Hatten
Oh, I get it now. You're physically handicapped! I'm so sorry. Maybe you need a Health Care Aide to help you up when you fall. Dr.1 Driver "There's a Hun in the sun!"
Reply to
Dr1Driver
| Take a fresh bottle of CA, weigh it, squirt some accelerator into it | (and jump out of the way), and then weigh it again when it's set. | The bottle of glue will weigh the same (if you take into account the | amount that boiled over and/or flew somewhere else).
Hey now -- quit trying to confuse the issue with easily verified facts!
(:
Reply to
Doug McLaren
Must be all that hitting your head when you fall off your chair that makes you so dumb, I guess.
CA cures through a chemical reaction. It has no water or solvents in it so it can't "dry".
-- Paul McIntosh
Reply to
Paul McIntosh
Isn't it the water in the air that causes CA to cure ? If so the addition of water molecules to the mix may actually result in cured CA weighing more that liquid CA.
Reply to
Oper8 On U
That's what I always understood. But then, I'm no chemist. Maybe the newer stuff uses something else.
Would make sense to a point. Next question would be how much of that water evaporates as a result of the whole process? But I'll let Bill answer that one! :)
Reply to
C.O.Jones
i just depends on how dry it is in your area.
I will always buy or fly a basement built plane then a garage built plane.
Reason why does your basement jump in temperature or humidity as much as your garage. ???
Assemble 2 exact shaped pieces of balsa with any glue you want (literally i mean any glue) keep one in the basement and the other in your garage then compare after a week .
warp city here we come ....if you live in New Mexico don't even bother answering this
my 2 CDNcent's
Reply to
Sylvia Dulude
I doubt if your use of CA would make any measurable difference. What is MUCH more likely is that there is a difference in wood density between the wood used on either side of the wing. This is not, however, a bid deal. Wings, for the reason mentioned above, frequently need to be laterally balanced. The easiest and most accurate way to do that is to put assemble the two wing halves together and then balance the entire assemble. You do NOT have to weight anything; what you're going to see is that one side of the wing will droop. All you have to do is start adding pennies (my favorite) or a washers or whatever just inside the tip of the high wing until the assembly balances. Then epoxy those weights inside the wing tip where you won't see them once it's covered. KEEP IN MIND that epoxy has weight too, so just glue in MOST of whatever weights you use and then check it again for balance once the epoxy kicks. You might have it so close that just dabbing in more epoxy will finish the balancing act.
MJC
Reply to
MJC
Wait until you have the plane finished and all together, then do a lateral balance. The lateral balance will change depending on other issues such as engine and muffler location, etc.
John VB
Reply to
jjvb
You need to protect your head when you fall off the chair.
Since I spend a good part of my time at work in a chemical laboratory, I decided yesterday afternoon to "dry" some samples of various CA adhesives and measure weight loss. I carefully weighed a few samples of thin and medium CA on an analytical balance accurate to 1/10 milligram. These samples were held in laboratory weighing dishes. To kick them off (as the surface chemistry of a sterile weigh dish will not catalyze CA for ages or ever), I treated several strips of paper with raw CA catalyst (no solvent, CA kicker is usually about 2% catalyst and 98% solvent) which I lay across the top of the weigh tin so that the catalyst (which is somewhat volatile) would do it's trick overnight.
This morning I checked the samples, and they were all fully cured, hard as nails. So I weighed them.
Gosh, surprise surprise! The weight loss varies between zero and one half a percent. As these are small samples some of that 1/2% can likely be attributed to weighing error. Some might be volatiles in the adhesive wandering off. At that level who cares.
NO significant weight loss. In fact numbers like that equate to NO weight loss.
So.. rather than continue to argue perhaps you should simply realize that you have your facts wrong. This information could actually be useful to you.
And btw, I do know the difference between wet and dry. Do you now understand the difference between drying and curing? Dr.1 does, Paul does, I do.
Mike D.
Reply to
M Dennett
Wow, it got quiet here all of a sudden, didn't it?
Mike D.
Reply to
M Dennett
ROFLOL! It never ceases to amaze me how many disdain hard factual data. You have spoiled their fun
Reply to
Six_O'Clock_High

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